METHODS AND SYSTEMS RELATING TO OVERCURRENT CIRCUIT PROTECTION

• US 20100214709A1
• Filed: 02/20/2009
• Published: 08/26/2010
• Est. Priority Date: 02/20/2009
• Status: Active Grant

• Current Assignee: Won-Door Corporation (Sanwa Holdings Corp.)
• Original Assignee: Won-Door Corporation (Sanwa Holdings Corp.)
• Inventors: Banta, Kevin D., Hall, Duane O., Goodman, E. Carl, Field, D. George
• Granted Patent: US 8,279,565 B2
• Time in Patent Office: Days
• US Class Current: 361/93.900
• CPC Class Codes: H02H 3/006 Calibration or setting of parameters
• CPC Class Codes: H02H 7/0816 concerning the starting sequence, e.g. limiting the number of starts per time unit, monitoring speed during starting

Abstract

Systems and methods for providing overcurrent circuit protection are disclosed. A method of providing overcurrent circuit protection may include setting a threshold current value according to an operational state of a motor and sensing an amount of current being supplied to the motor. The method may further include electrically isolating the motor from a current source if the sensed current amount is greater than the threshold current value.

Claims

1. A method of operating an overcurrent protection control system, comprising;

monitoring an operational state of a motor;

defining a threshold current value of the control system responsive to the operational state of the motor;

sensing an amount of current being supplied from a power source to the motor;

comparing the sensed current amount and the threshold current value; and

electrically isolating the power source from the motor if the sensed current amount exceeds the threshold current value.

2. The method of claim 1, wherein electrically isolating the power source from the motor comprises conveying a signal from a microprocessor to a gate of a Field Effect Transistor (FET) operably coupled between the power source and the motor to cause the Field Effect Transistor (FET) to operate in a non-conductive state.

3. The method of claim 1, wherein defining a threshold current value comprises defining a threshold current value as an “

off”

current value while the motor is in an “

off”

operational state.

4. The method of claim 1, wherein defining a threshold current value comprises defining a threshold current value as a “

first duration start up”

current value while the motor is in a first time period of a “

start up”

operational state.

5. The method of claim 1, wherein defining a threshold current value comprises defining a threshold current value as a “

second duration start up”

current value while the motor is in a second time period of a “

start up”

operational state.

6. The method of claim 1, wherein defining a threshold current value comprises defining a threshold current value as a “

steady state”

current value while the motor is in a “

steady state”

operational state.

7. The method of claim 1, wherein sensing an amount of current comprises sensing an amount of current being supplied from the power source to the motor with a Hall Effect current sensor.

8. The method of claim 1, wherein monitoring an operational state of a motor comprises receiving one or more status signals at a microprocessor indicative of the operational state of the motor.

9. The method of claim 1, further comprising initiating a time delay after electrically isolating the power source from the motor and electrically coupling the power source to the motor upon completion of the time delay.

10. The method of claim 9, wherein initiating a time delay comprises initiating a time delay of 1.5 seconds.

11. The method of claim 1, wherein defining a threshold current value comprises defining a threshold current value as a “

start up”

current value while the motor is in a “

start up”

operational state.

12. The method of claim 1, wherein sensing an amount of current, comparing the sensed current amount and the threshold current value, and electrically isolating the power source from the motor is affected in substantially 200 microseconds or less.

13. A method of providing overcurrent circuit protection, comprising:

defining a threshold current value according to an operational state of a motor;

sensing an amount of current being supplied to the motor; and

electrically isolating the motor from a power source if the sensed current amount is greater than the threshold current value.

14. The method of claim 13, further comprising initiating a time delay after electrically isolating the motor from the power source and electrically coupling the power source to the motor upon completion of the time delay.

15. The method of claim 14, wherein initiating a time delay comprises initiating a time delay of 1.5 seconds.

16. The method of claim 13, wherein defining a threshold current value comprises defining and storing a threshold current value in a microprocessor.

17. The method of claim 13, wherein defining a threshold current value comprises defining a threshold current value according to one of an “

off”

operational state of the motor, a “

start up”

operational state of the motor, and a “

steady state”

operational state of the motor.

18. The method of claim 17, wherein electrically isolating the motor from a current source comprises comparing the sensed current amount and the threshold current value with a microprocessor and transmitting a signal to a switching element to electrically isolate the motor from a current source if the sensed current amount is greater than the threshold current value.

19. An overcurrent protection control system, comprising:

a motor control device operably coupled to an electrical load;

a microprocessor operably coupled to the motor control device and configured to receive one or more status signals indicative of an operational state of the electrical load, the microprocessor further configured to set a threshold current value according to the operational state of the electrical load;

a current sensor operably coupled between a power source and the motor control device and configured to sense an amount of current delivered to the motor control device, the current sensor further configured to convey a signal to the microprocessor indicative of the sensed current amount; and

a switching element operably coupled between the power source and the motor control device and configured to receive a signal from the microprocessor and either electrically isolate the power source from the motor control device or electrically couple the power source to the motor control device;

wherein the microprocessor is further configured to compare the sensed current amount and the threshold current value and convey a signal to the switching element to cause the switching element to electrically isolate the power source from the motor control device if the sensed current amount is greater than the threshold current value.

20. The overcurrent protection control system of claim 19, wherein the motor control device comprises:

another microprocessor configured to define and store another threshold current value according to the operational state of the electrical load; and

another current sensor operably coupled between the power source and the motor and configured to sense another amount of current delivered to the motor, the another current sensor further configured to convey a signal to the another microprocessor indicative of the another sensed current amount;

wherein the another microprocessor is further configured to compare the another sensed current amount and the another threshold current value and convey a signal to a another switching element to cause the another switching element to electrically isolate the motor from the power source if the another sensed current amount is greater than the another threshold current value.

21. The overcurrent protection control system of claim 19, wherein the current sensor comprises a Hall Effect current sensor.

22. The overcurrent protection control system of claim 19, wherein the microprocessor is configured to set the threshold current value to an “

off”

current value when the motor is in an “

off”

operational state.

23. The overcurrent protection control system of claim 19, wherein the microprocessor is configured to set the threshold current value to a “

first duration start up”

current value when the motor is in a first time duration of a “

start-up”

operational state.

24. The overcurrent protection control system of claim 19, wherein the microprocessor is configured to set the threshold current value to a “

second duration start up”

current value when the motor is in a second time duration of a “

start-up”

operational state.

25. The overcurrent protection control system of claim 19, wherein the microprocessor is configured to set the threshold current value to a “

steady state”

current value when the motor is in a “

steady state”

operational state.

26. The overcurrent protection control system of claim 19, wherein the microprocessor is configured to initiate a time delay after sending a signal to the switching element to electrically isolate the power source from the motor control device and upon completion of the time delay to send a signal to the switching element to electrically couple the power source to the motor control device.

27. The overcurrent protection control system of claim 19, wherein the overcurrent protection control system is configured to sense an amount of current delivered to the motor control device, compare the sensed current amount and the threshold current value, and electrically isolate the power source from the motor control device in substantially 200 microseconds or less.

28. The overcurrent protection control system of claim 19, wherein the switching element comprises a Field Effect Transistor (FET).

29. The overcurrent protection control system of claim 28, wherein the microprocessor is configured to send a signal to a gate of the Field Effect Transistor (FET).

30. An overcurrent protection control system, comprising:

a motor control device operably coupled between a power source and a motor, the motor control device comprising;

a microprocessor configured to define and store a threshold current value according to an operational state of the motor; and

a current sensor operably coupled between the power source and the motor and configured to sense an amount of current delivered to the motor, the current sensor further configured to convey a signal to the microprocessor indicative of the sensed current amount;

wherein the microprocessor is further configured to compare the sensed current amount and the threshold current value and convey a signal to a switching element to cause the switching element to electrically isolate the motor from the motor control device and the power source if the sensed current amount is greater than the threshold current value;

wherein the switching element is operably coupled between the motor control device and the motor and configured to receive a signal from the microprocessor and either electrically isolate the motor from the motor control device and the power source or electrically couple the motor to the motor control device.

31. The overcurrent protection control system of claim 30, wherein the microprocessor is configured to initiate a time delay after sending a signal to the switching element to electrically isolate the motor from the motor control device and upon completion of the time delay to send a signal to the switching element to electrically couple the motor to the motor control device.